The Weplay Air Cushion is an inflatable balloon, that mimics both the movement and shape of the gym ball. It can be used on the floor to strengthen lower body muscles, as well as train for balance. One side of the cushion is very bumpy while the other side is slightly bumpy. This provides the users with different sensations to enhance the sense of touch and coordination. Diameter: 14″. Ages: 2 years & up.